Hard to choose between ET, original Kong on the Studio Tour, and BTTF. Loved all of them for different reasons.
The one that would benefit the park the most would be ET. It needs a beautiful family friendly dark ride like it was, and it had a long ride time.
As a huge BTTF fan, I'd wanna see BTTF back. I never got tired of it. It was the best. Gave me the chills and I still miss jt.
BUT with so many simulators at the park, I'll have to choose ET.